举报
woslisulai
假如你证明那个式子是小于2-1/2^n,那肯定是小于2 的对吧?数学归纳。n=1,成立。 n=k,(1+1/b1)(1+1/b2)……(1+1/bk)<2-1/2^k,·······下面的bk+1,k+1是下标 n=k+1,(1+1/b1)(1+1/b2)……(1+1/bk+1)<(2-1/2^k)(1+1/bk+1)=2-1/2^k+2/bk+1-1/(2^k*bk+1)=2-1/2^(k+1)-1/2^(k+1)+2/bk+1-1/(2^k*bk+1)<2-1/2^(k+1).,,然后下面就没问题了